Potential DCSync (Windows Event Log)

Group by: _time, host
Source: github.com/anvilogic-forge/armory

Adversaries may attempt to access credentials and other sensitive information by abusing a Windows Domain Controller's application programming interface (API) to simulate the replication process from a remote domain controller using a technique called DCSync

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1003.006` OS Credential Dumping: DCSync

References

https://blog.blacklanternsecurity.com/p/detecting-dcsync

Telemetry coverage

Provider	Record / event type
Security-Auditing	Event ID 4662: An operation was performed on an object.

Rule body

id: '13811.20280'
title: Potential DCSync
description: 'Adversaries may attempt to access credentials and other sensitive information
  by abusing a Windows Domain Controller''s application programming interface (API)
  to simulate the replication process from a remote domain controller using a technique
  called DCSync. -- Threat Actor Association: FIN8 (Syssphinx), Muddled Libra'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4662) OR
  "<EventID>4662<") "0x100" ("Replicating Directory Changes all" OR "1131f6ad-9c07-11d1-f79f-00c04fc2dcd2"
  OR "1131f6aa-9c07-11d1-f79f-00c04fc2dcd2" OR "9923a32a-3607-11d2-b9be-0000f87a36b2"
  OR "89e95b76-444d-4c62-991a-0facbeda640c") |regex user!=".*\$" | table _time, host,
  user process, process_*, signature_id, parent_*, parameters | bin span=1s | stats
  values(*) as * by _time, host '
techniques:
- credential-access:os credential dumping:dcsync
technique_id:
- T1003.006
data_category:
- Windows event logs
references:
- https://blog.blacklanternsecurity.com/p/detecting-dcsync

Stages and Predicates

Stage 1: `search`

`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4662) OR "<EventID>4662<") "0x100" ("Replicating Directory Changes all" OR "1131f6ad-9c07-11d1-f79f-00c04fc2dcd2" OR "1131f6aa-9c07-11d1-f79f-00c04fc2dcd2" OR "9923a32a-3607-11d2-b9be-0000f87a36b2" OR "89e95b76-444d-4c62-991a-0facbeda640c")

Stage 2: `regex`

| regex user!=".*\$"

Stage 3: `table`

| table _time, host, user process, process_*, signature_id, parent_*, parameters

Stage 4: `bucket`

| bin span=1s

Stage 5: `stats`

| stats values(*) as * by _time, host

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`user`	regex_match	`".*$"`	`excludes:user`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`EventCode`	eq	`4662` corpus 15 (splunk 7, kusto 4, elastic 3, chronicle 1)	`field:"EventID" kind:eq value:"4662"`

Search terms

These SPL tokens match against raw event text.

Stage	Term
1	`"<EventID>4662<"`
1	`"0x100"`
1	`"Replicating Directory Changes all"`
1	`"1131f6ad-9c07-11d1-f79f-00c04fc2dcd2"`
1	`"1131f6aa-9c07-11d1-f79f-00c04fc2dcd2"`
1	`"9923a32a-3607-11d2-b9be-0000f87a36b2"`
1	`"89e95b76-444d-4c62-991a-0facbeda640c"`